Manufacture of magnesia.



UNITED STATES PAEENT amt- EMANUEL e. zms, or 3mm, MARYLAND, assrenon no one srmaan nm'n it STONE COMPANY, OF BALTIMORE, HA RY LAND, A. WRATION O! WEST VIB- Patented July 2, 1912.

GINIA. i

MANUFACTURE OF MAGNESIA.

1,031,502, Specification of Letters Patent.

No Drawing.

5 To all whom it may concern:

Be it known that I, EMANUEL G. ZIES, of Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Manufacture of Magnesia; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The primary object of this invention is to provide a simple and etficaciousprocess of chemically separating calcium and magnesium when these elements are present in such combinations as are found in magnesian limestone, dolomite, and crude magnesite.

While the invention is especially applicable to the treatment of dolomite, magnesian limestone or crude magnesite may be treated equally as well as dolomite.

The dolomite is calcined in order to drive I off all carbon dio'xid. This calcining is pref- ,erably carried out in a kiln constructed to permit the removal of the carbon dioxidby means of a pump. This calcined dolomlbe,

- consisting of calcium oxid and magnesium oxid, is then ground, preferably fine enough to pass through a thirty (30) mesh screen, but I do not, however, limit myself to this degree of fineness.

-A solution of calcium chlorid is brought into intimate mixture with the dry ground calcined dolomite, and the whole is treated in a closed tank with carbon dioxid, preferably that obtained from the kiln in which the dolomite was calcined. The calcium compounds are thereby carbonated while the magnesium is converted directly from the oxid to the chlorid, which being soluble remains in solution and is subsequently separated from the insoluble calcium carbonate by any of the well known methods, such as filtration, decantation or centrifugal force. By this procedure, slaking or recarbonating of the calcined dolomite previous to adding the solution of calcium chlorid and the carbon dioxid, is not necessary; also, by this procedure carbonatingof the magnesium oxid does not take place.

When, as has heretofore been proposed, magnesium carbonate is treated with a solution of calcium chlorid, magnesium chlorid is slowly formed as a result of mass action. In order to bring about this reaction a large Application filed January 13, .1912. Serial No. 671,008.

excess of calcium chlorid, over thatrequired to convert the magnesium oxid into magneslum chlorid, is necessary, and consequently-the resulting magnesium chlorid is contaminated with thisexcess calcium chlorid. According to my method this cannot occur; and if carried out as previously described, and an amount of calcined dolomite containing a quantity of magnesium oxid chemically equivalent to the amount of calcium chlorid, is used, then all of the chloridin the calcium chlorid is utilized to form magnesium chlorid, the calcium being precipitated as calcium carbonate. The result ing magnesium chlorid can either be used as such or can-be precipitated with calcined dolomite, forming magnesium hydroxid and reforming calcium chlorid. This is followed by the separation of the insoluble magnesium compound from the soluble calcium compound. On properly calcining this precipitated magnesium hydroxid, a very dense magnesium oxid is obtained.

I claim as my invention:

1. The herein described method of" separating calcium and magnesium in dolomite, or magnesium limestone, or crude magnesite, which consists in calcining the dolomite or its equivalent, bringing the dry calcined material into an intimate mixture with a solution of chlorid of calcium, passing carbon dioxid into this mixture and the subsequent separation of the soluble magnesium chlorid from-the insoluble calcium carbonate.

2. The herein described method of separating calcium and magnesium in dolomite, or magnesium l1mestone,or crude magnesite,

which consists in calcining the dolomite or,

- rating calcium and magnesium in dolomite,

or magnesium limestone, or crude magnesite, which consists in calcining the dolomite}?! 7 its equivalent, bringing the dry calci gdl material into an intimate mixturey h" solution of chlorid of calcium, passrngcar bon dioxid into this mixture, then liy pre- Intestimony whereof, I'have signed this cipitationwith calcined dolomite forming specification in the presence of two Subsc-rib from the magnesium chlorid magnesium ing witnesses. hydroxid and reforming calcium chlorid,

y 5 and then separat' all the insoluble mag- Witnesses:

nesium compound m the soluble calcium DANIEL BAKER, compound. G. E. DE Hon.

EMANUEL G. ZIES. 

